Flowable Fill

Flowable fill is a self-compacting, self-leveling that is highly flowable and considerably lower strength material. It is placed with minimal effort and does not require vibration or manual compaction. It hardens into a crusty material with strengths less than 1200 psi and can be excavated if needed.

Flowable fill is an economically excellent solution for filling inaccessible areas, underground tanks, sewers and utility trenches. Other applications include conduit encasement, pile excavations, sub-base, wells, voids under pavement and erosion control.

Other terms this product may be referred to as is controlled low strength material or CLSM, unshrinkable fill, controlled density fill, flowable mortar or lean-mix backfill.


Grout is used to fill space or cavities and provide continuity between building elements. Grout is composed of a cementitious material, fine aggregate and a sufficient amount of water to produce a fluid, flowable mixture. Masonry grout has specified strengths of at least 2000 psi. Grout is poured with a significantly higher water content as it is poured into absorptive forms – masonry unit cells or cores. Mortar, unlike grout, contains hydrated lime and only enough water to make it workable.